Vibration dampers having an arrangement mentioned above have been disclosed in Japanese Patent Application Laid-Open Publication No. 2012-225482, Japanese Patent Application Laid-open Publication No. 2010-001905, and Japanese Patent Application Laid-open Publication No. Hei 9-196122. In Japanese Patent Laid-open Publication No. 2012-225482 for instance, a vibration damper which includes a shock-absorbing member for absorbing torsional vibrations, and an inertial body that generates an inertial torque acting on a power transmission route has been described. In this vibration damper, the inertial body is connected to a sun gear of a planetary gear mechanism via a centrifugal clutch. In Japanese Patent Application Laid-open Publication No. 2010-001905, a vibration damper which includes a planetary gear mechanism having a sun gear that rotates integrally with an inertial body, a carrier that rotates integrally with an input shaft of a transmission, and a ring gear that is fixed selectively by a brake unit, has been described. In this vibration damper, the carrier of the planetary gear mechanism is connected to an engine via a damper that absorbs a fluctuation in torque. Moreover, in Japanese Patent Application Laid-open Publication No. Hei 9-196122, making a carrier of a planetary gear mechanism function as an inertial body has been disclosed.
However, in the vibration damper described in each of the abovementioned patent literature, it is possible to damp the torsional vibrations by making a damping force by the shock-absorbing member and the inertial body act on the power transmission route, but a response of a vehicle is degraded due to the damping force.